| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 10 |
| 3 | 45 |
| 4 | 190 |
| 5 | 930 |
| 6 | 4660 |
| 7 | 24445 |
| 8 | 131190 |
| 9 | 719830 |
| 10 | 4013260 |
| 11 | 22684370 |
| 12 | 129661740 |
| 13 | 748252580 |
| 14 | 4353379560 |
| 15 | 25508284445 |
| 16 | 150392391590 |
| 17 | 891549228430 |
| 18 | 5310994644060 |
| 19 | 31775749689670 |
| 20 | 190860711108740 |
| 21 | 1150473009844380 |
[1,5,10,45,190,930,4660,24445,131190,719830, 4013260,22684370,129661740,748252580,4353379560, 25508284445,150392391590,891549228430, 5310994644060,31775749689670,190860711108740, 1150473009844380] |